1. Field of the Invention
The present invention relates to a method and to a device for locally recorrecting standard color corrections in color picture recording by means of color reproduction devices, in which an addressable memory is provided for the color correction and emits a plurality of digitalized, trichromatic image scanning values and a corresponding plurality of corrected image recording signals as output values, whereby the assignment of memory input to memory output values is stepped into the memory before the reproduction is standardized color correction data.
2. Description of the Prior Art
A method for color correction is disclosed in U.S. Pat. No. 2,993,087 in which an opto-electronic scanning device scans an original, a memory for the color correction information is provided, and a recording unit records corrected color pictures or corrected color separations. After a trichromatic color separation, the scanning unit supplies primary color measuring value signals which are fed to the memory after digitalization, the memory containing the color correction parameters stored in the form of a schedule. If required, a transformation, i.e. matrixing of the color measuring value signals, can be carried out before or after the digitalization. In the case of a transformation, a corresponding output value combination of printing ink signals mg, cy, ye, bl are output for each input value combination of the digitalized color measuring values R, G, B or R', G', B', the printing ink signals containing a previously determined color correction which is aimed at in the standard case. This color correction represents a conversion of the assignment between the primary color measuring value signals R, G, B and the printing ink signals mg, cy, ye, bl. The printing ink signals obtained by means of the correction control the individual printing ink amounts during recording or, respectively, indicate a measure in that color separations for the appropriate printing density during printing. The basic principle of such a color correction unit can be basically stated by the following functional relationship:
Initial values (cy, mg, ye, bl)=F (scanning values R,G,B).
For devices of the type initially described above, the manufacturer makes available a library of standard assignments as so-called color correction sets with reproduction behavior optimized for specific pattern categories and printing conditions, the color correction sets being optionally input into the correction memory as so-called standard corrections. In comparison to previous, analog correction methods, this type of correction is more simple since the setting of color parameters is eliminated, but it has the disadvantage that it is not as flexible.